Powassan encephalitis is a rare tick born disease caused by a virus from the family Flaviviridae, genus Flavivirus. While the patients can have variable presentations including headache, nausea, confusion, seizures, weakness, coma; mood disorders as a part of the presentation has not been reported. Abulia is a state of diminished motivation characterized by apathy and delayed response to questioning.

MRI brain with and without contrast showed non-enhancing, white matter FLAIR hyperintense lesions of the frontal lobes bilaterally, largest on the right frontal centrum semiovale. Her CSF analysis was notable for lymphocytic pleocytosis. The screening for Powassan virus with IgM capture enzyme-linked immunosorbent assay came positive both in serum and CSF.